1. Field of Invention
The present invention belongs to an seepage-proofing and reinforcement field of infrastructures such as water conservancy, mine, and environmental protection, more particularly to a grouting method of an ultra-thin polymer anti-seepage wall related to an embankment, earth dam, tailing dam, interception-pollutant dam seepage-proofing and reinforcement.
2. Description of Related Arts
Since the founding of People's Republic of China, the water conservancy, mining, environmental protection and other infrastructures of China have made remarkable achievements, and have played important roles in China's economic development and social progress. In the field of water conservancy infrastructure, the water conservancy infrastructures are built in the '50s˜'70s. Limited to the economic and technological conditions, many reservoir design and construction quality are inadequate. After long-running, the problems that long-term disrepair, serious aging and dangerousness are serious. At present, 87,000 reservoirs of various types have been built, ranking the first in the world. About 40% small-sized reservoirs and 25% medium-sized reservoirs are in danger, they are great threats to people's lives and properties, and social stability. During a long history of dam construction, the majority are formed by heightening and thickening over the years, the construction soils on the body are from different periods, the construction quality can not meet the design requirements, and thus there are different security risks. Among the over 40000 existing dangerous reservoirs in China, more than 90% are built with rock and soil, and the majority are built by soil. According to the preliminary calculations, more than 50% of the small reservoirs need seepage controlling and reinforcing. In the field of mining infrastructure, the tailings dams are the major facilities of mining beneficiating production, which are also the accident-prone parts and the source of security risks. Furthermore, there are kinds of toxic and hazardous substances in the tailings dams which are man-made stone and soil flowing area of a high potential, the safe operation is directly related to the safety of life and property of the people living at downstream and the ecological environment of the surrounding areas of the tailings dams. In the great amount of tailings dams in China, less than 70% are in normal operation currently, and more than 40% are at risky, diseased, expired services status, so catastrophic accidents occur frequently. Seepage is one of the major reasons that the tailings dams have accidents. How to effectively control the seepage for ensuring the safe operation of the tailings dams is terribly urgent and important. In the field of environmental protection infrastructure, according to statistics, in current landfills, more than 95% are simply buried and quasi sanitary landfill, since the horizontal impervious measures are not used in most landfills, and the exhaust system for the leachate at bottom is not perfect, which results in a large amounts of untreated leachate directly seeping into the soil and the groundwater to cause serious pollution to the environment. In recent years, people take more and more attention on the landfill problems, new landfills are established in many provinces. However, the quantity and scale of the landfills can not meet the requirement of the growing domestic garbage, the real innocuous disposal garbage is only 2.3%. The main problem that how to prevent the leachate seepage pollution should be considered at first. The leachate seepage pollution can be properly treated by seepage-proofing on the interception-pollutant dam, but the geographical environment and the geological condition of the most landfills can not meet the requirement of seepage-proofing.
Thus, seepage is a common problem which the water conservancy, mine, and environmental protection infrastructures such as the earth dams, the tailing dams, and the interception-pollutant dams have, the seepage-proofing and reinforcement on these infrastructures are long-term and arduous tasks we should face. The seepage-proofing technologies widely used in engineering include concrete anti-seepage wall technology, cement mixing pile technology, and jet grouting technology etc. These seepage-proofing technologies widely used in China have played an important role in the seepage-proofing and reinforcement of the infrastructures such as the large reservoirs, the tailings, and landfills, but there are still some technical deficiencies. In the field of anti-seepage wall material, conventional anti-seepage walls materials are the cement-like, wherein the anti-seepage walls constructed are rigid, which are different from the soil elastic modulus, wherein the impermeability and the crack resistance are inadequate. In the wall building mechanism, materials are easy to separated from soil, and it is hard to grout into a complete and continuous wall according to the conventional anti-seepage wall building seepage-proofing technology; In the way of construction, anti-seepage walls are formed by grooving, stirring, spraying and vibrating on the soil in the conventional anti-seepage wall building technology, the dams are badly destructed by disturbance. The problems that the unequally stirring, grout pouring, unreasonable loading, and discontinuous pile body lead to low pile strength, poor construction quality, and non-ideal seepage effect. The slurry gets great energy by the high-pressure device according to the high-pressure jet grouting technology. Thus, the anti-seepage technology widely used in the engineering has the shortcomings of large disturbance destruction, long duration, high cost, and inconvenient construction, especially to a large number of the small and medium-sized dams, the conventional technology is limited by not only the funding, but also the bulky equipment and the difficult entering, which are not adapt to the present developing demand of the anti-seepage and reinforcement technology of the dams, the tailing dams and the sewage dams. Therefore, speeding up the research of the new materials, new technology, and new equipment are the solutions of the significant science and technology problems which are met in the conventional anti-seepage and reinforcement technology of the embankments, the earth dams, the tailing dams, the interception-pollutant dams of the infrastructures such as water conservancy, mine, and environmental protection.
Polymer grouting technology is one of the foundation rapid reinforcement technologies which has developed since the 1970s. The polymer materials are injected into the foundation by the property that a volume rapidly expands after the polymer materials react to reinforce the foundation, fill the blank space, and lift the floor. At present, the polymer grouting technology is mainly used in the field of foundation reinforcement of the industrial and the civil buildings and the road maintenance. In recent years, the invention dedicates to the research and development of the dam anti-seepage polymer grouting technology with respect to the developing demand of the dam reinforcement and the deficiencies existed in the conventional dam anti-seepage technology, and has filed the patent applications having numbers of CN200910066334.8 and CN200910066335.2, creating a new way to build ultra-thin polymer anti-seepage bodies, which are, however, massive connected, and hard to form a continuous anti-seepage system.